The present embodiments relate to a coil arrangement for a magnetic resonance tomography system.
Magnetic resonance devices for examining objects or patients using magnetic resonance tomography (e.g., magnetic resonance imaging) are known, for example, from DE10314215B4, U.S. Ser. No. 12/392,537, US20080094064A1 and U.S. Pat. No. 7,417,432B2.
In MR tomography, images having a high signal-to-noise ratio are acquired using local coil arrangements (e.g., loops, local coils). MR tomography includes exciting nuclei of an examination subject (e.g., a patient) to emit radiation, causing a voltage to be induced in a coil receiving the radiation. The voltage is amplified using a low-noise preamplifier (e.g., LNA) and forwarded at the MR frequency via cable to receive electronics. In order to improve the signal-to-noise ratio, including in the case of high-resolution images, use is made of high-field systems. The basic field strengths of the high-field systems range up to around 3 Tesla and higher. Since the high-field system enables more coil elements (e.g., loops) to be connected to an MR receiving system than there are receivers present, a switching array (e.g., an RCCS), for example, is installed between receive antennas and receivers. The switching array routes the currently active receive channels to the receivers present. This enables more coil elements to be connected than there are receivers present, since in the case of whole-body coverage, coils that are located in the field of view (FoV) or in the homogeneity volume of the magnet may only be read out.
In the following description, the individual antennas of a coil arrangement are also referred to as coil elements. A coil arrangement may include one coil element or (in the case of an array coil) a plurality of coil elements. A coil arrangement includes (e.g., in the case of a local coil) the coil elements (e.g., antennas), the preamplifier, further electronics and cabling, a housing, and may include a cable with plug, using which the coil arrangement is connected to the system. An “MRT system” may be an MR scanner facility. A patient, for example, lies in an MR scanner on a spine array coil integrated in a table (e.g., a patient couch) and, for example, on the lower part (posterior part) of a head coil. All the other coils or coil parts (e.g., anterior part head, anterior abdomen coils (body matrix), peripheral angio array (PAA) coils) may be attached close to the body on the anterior side (e.g., upper side) of the patient. In this case, some of the coils are placed directly onto the patient (e.g., body matrix coil, PAA), or the coils enclose the anatomy of the patient close to the body (e.g., a head coil).
Imaging using a body coil alone as a receive antenna does not produce the desired image quality, and this approach is not suited for use in parallel imaging. When local coils are disposed at a greater distance from the patient, the inherent noise of the local coil becomes increasingly dominant, leading to poor image quality, for which reason the coils may be deployed as close as possible to the body.